是否可以写出类似于下面的内容?

public const string[] Titles = { "German", "Spanish", "Corrects", "Wrongs" };

当前回答

快速的解决方法,说不定对别人有帮助。我需要一个字符串[]作为Attribute的参数(在某些理论中为测试用例传递内联数据)。Readonly在这里没用。但是,我最后做的是:

const string foo = "a|b|c";

[InlineData(foo)]
public void Test(string fooString)
{
    var foo = fooString.Split("|"); // foo == {"a","b","c"}
    ...
}

其他回答

如果你在IReadOnlyList接口后面声明了一个数组,你会得到一个常量数组,在运行时声明常量值:

public readonly IReadOnlyList<string> Titles = new [] {"German", "Spanish", "Corrects", "Wrongs" };

在. net 4.5及更高版本中可用。

.NET Framework v4.5+解决方案,改进了tdbeckett的答案:

using System.Collections.ObjectModel;

// ...

public ReadOnlyCollection<string> Titles { get; } = new ReadOnlyCollection<string>(
  new string[] { "German", "Spanish", "Corrects", "Wrongs" }
);

注意:假定集合在概念上是常量,在类级别声明它时将其设置为静态可能是有意义的。

上面的:

Initializes the property's implicit backing field once with the array. Note that { get; } - i.e., declaring only a property getter - is what makes the property itself implicitly read-only (trying to combine readonly with { get; } is actually a syntax error). Alternatively, you could just omit the { get; } and add readonly to create a field instead of a property, as in the question, but exposing public data members as properties rather than fields is a good habit to form. Creates an array-like structure (allowing indexed access) that is truly and robustly read-only (conceptually constant, once created), both with respect to: preventing modification of the collection as a whole (such as by removing or adding elements, or by assigning a new collection to the variable). preventing modification of individual elements. (Even indirect modification isn't possible - unlike with an IReadOnlyList<T> solution, where a (string[]) cast can be used to gain write access to the elements, as shown in mjepsen's helpful answer. The same vulnerability applies to the IReadOnlyCollection<T> interface, which, despite the similarity in name to class ReadOnlyCollection, does not even support indexed access, making it fundamentally unsuitable for providing array-like access.)

我相信你只能让它只读。

为了完整起见,现在我们也有immutablearray供我们使用。这应该是真正不可变的:

public readonly static ImmutableArray<string> Titles =
    ImmutableArray.Create(new[] { "German", "Spanish", "Corrects", "Wrongs" });

需要System.Collections.Immutable NuGet引用。

数组可能是一种只能在这里求值的东西 运行时。常量必须在编译时求值。尝试使用"readonly" 而不是"const"。